1. Field of the Invention
The present invention relates to a lens structure, and more particularly to a bifocal double group lens assembly with both zoom and focus functions, the first lens group is stationary, and the second lens group is driven by a linear driver.
2. Description of the Prior Art
Since image lens is used more and more widely in modern society, and particularly, image taking has been one of indispensable functions of the mobile phone product. However, the lens assembly in the product also needs to be miniaturized and thinned due to the requirement for portability. Therefore, within a set size, how to develop an image lens assembly with zoom and focus capability has become the focus of research of the advanced mobile phone's lens assembly.
Conventionally, a double group zoom lens needs a driver to drive the CAM barrel when zooming, so as to make the first lens group and the second lens group move synchronously. When focusing, the lens assembly needs another independent driver to drive the first lens group. Although this technique achieves the function of zooming and focusing, it still has the following disadvantages:
Firstly, this double group zoom lens requires two lens groups to move synchronously, and has too many moveable members, as a result, the reliability of the product is decreased.
Secondly, zooming and focusing operation of this double group zoom lens are executed separately by two independent drivers, therefore, the cost and the size of the lens assembly cannot be controlled effectively.
Thirdly, the zooming mechanism of this double group zoom lens usually consists of a CAM barrel and a driver, so its structure is complicated, mould cost is high, and size is large.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.